Conventionally, in a construction using a steel pipe column, there is a case in which a beam of H shaped steel is connected. To connect the column and the beam, a through-diaphragm corresponding to the height of a flange part of the beam is provided to transfer stress from the beam to the column efficiently at a connecting part thereof. The through-diaphragm is a plate-like member that is connected by welding and the like between a column and a column. Generally, the flange part of the beam is butted against the side surface of the through-diaphragm to be welded.
However, there are cases in which the sizes (heights) of the beams that are connected to the column are not equal in all directions. For example, there is a case in which a beam having a shorter height is connected in only one direction. In such cases, it is impossible to connect at least one of the upper and lower flanges of the beam to the through-diaphragm to which other beams are connected.
Therefore, to connect such beams having different heights, connecting an inner diaphragm inside the column or the like is necessary.
Also, as a connection structure of column-and-beam to connect beams having different heights, there is a connection structure of column-and-beam wherein, a flange part of a beam is connected to a diaphragm, a beam connection member is connected between the other flange part of the beam and the other diaphragm, and stress is transferred between the beam and the diaphragm via the beam connection member (See Patent Document 1).